IP Addresses and Services Configuration Guide for Cisco 8000 Series Routers, IOS XR Releases

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IP Addresses and Services Configuration Guide for Cisco 8000 Series Routers, IOS XR Releases

LPTS components and packet delivery

Updated: August 12, 2026

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Describes the port arbitrator, flow managers, and IFIB that identify router-bound packet flows and deliver accepted packets to the correct route processor for application processing.

Local Packet Transport Services (LPTS) components maintain the packet-flow information that

  • identifies traffic destined for the secure domain router

  • associates accepted traffic with the intended router application, and

  • delivers packets to the correct route processor.

LPTS operates without required customer configuration. You can customize policer values and use operational commands to monitor flow managers and the port arbitrator.

Primary LPTS components

LPTS uses these components:

  • Port arbitrator: Maintains packet-flow tables for a logical router.

  • Flow managers: Coordinate with applications that receive packets from outside the router and maintain flow entries.

  • Internal Forwarding Information Base (IFIB): Describes packet flows and directs accepted packets to the correct route processor.

How LPTS packet delivery works

Router applications receive control and management traffic from outside the router. Local Packet Transport Services (LPTS) maintains the information required to identify and deliver this traffic securely.

Summary

The packet-delivery process uses these components:

  • Flow managers: Maintain flow information for applications.

  • Port arbitrator: Maintains packet-flow tables for the logical router.

  • Internal Forwarding Information Base (IFIB): Identifies the destination for an accepted packet.

Workflow

These stages describe how LPTS packet delivery works:

  1. The router examines an incoming packet that is destined for a router application and identifies its flow type from packet-header information.

  2. The programmed LPTS treatment determines whether the packet is accepted or dropped.

  3. For an accepted packet, LPTS uses the IFIB entry to select the correct route processor and application destination.

  4. The route processor receives the packet for application processing.

Result

Accepted router-bound packets reach their intended applications without allowing excess traffic to consume route processor resources.

LPTS flow types and TCAM capacity

Dynamic Local Packet Transport Services (LPTS) flow configuration is a per-line-card capability that

  • selects configurable flow types for programming in ternary content-addressable memory (TCAM)

  • sets the maximum number of entries for each selected flow type, and

  • allows different flow-capacity profiles across line cards.

The router programs default LPTS flow types and limits in TCAM during startup. A configured maximum of zero disables a configurable flow type.

TCAM capacity controls

Use show lpts pifib dynamic-flows statistics location to view configurable flow types, default limits, configured limits, hardware entries, software entries, and pending software entries.

  • Def_Max: Default maximum entry limit.

  • Conf_Max: Configured maximum entry limit.

  • HWCnt/ActLimit: Hardware entry count and actual maximum limit.

  • SWCnt: Software entry count.

  • P, (+): Pending software entries.

The combined maximum for all configured flow types must not exceed 16,000 entries per line card.

Hardware entry planning

Set the dynamic scale so that entries for the flow type remain in hardware. Adequate hardware capacity can help prevent session flaps for protocols such as BGP and OSPF during events such as route processor failover.

LPTS flow types

From IOS XR Release 26.3.1 onwards, the router supports these flow types:

  • IFIB_FT_IPSEC_KNOWN

  • FIB_FT_NTP_DEFAULT

  • IFIB_FT_TCP_LISTEN

  • IFIB_FT_PCEP

  • IFIB_FT_RADIUS

  • IFIB_FT_TACACS

  • IFIB_FT_RIP

  • IFIB_FT_EIGRP

  • IFIB_FT_SHTTP_DEFAULT

  • IFIB_FT_HTTP_DEFAULT

Configure the dynamic LPTS flow limits

Use this procedure to adjust per-line-card capacity for configurable Local Packet Transport Services (LPTS) flow types.

Before you begin

Use show lpts pifib dynamic-flows statistics location to record the current limits and available ternary content-addressable memory (TCAM) capacity.

Confirm that the combined maximum values do not exceed the capacity reported for the line card.

Procedure

  1. Configure the maximum entry value for each required flow type at the target location. Set a configurable flow type to zero when you must disable it to release capacity.

    Example:

    Router# configure
Router(config)# lpts pifib hardware dynamic-flows location 0/1/CPU0
Router(config-pifib-flows-per-node)# flow bgp known max 1800
Router(config-pifib-flows-per-node)# flow rsvp known max 0
Router(config-pifib-flows-per-node)# commit

    The line card reserves up to 1,800 entries for the BGP-known flow type and disables the RSVP-known flow type.

  2. Verify the committed dynamic-flow configuration.

    Example:

    Router# show running-config lpts pifib hardware dynamic-flows location 0/1/CPU0
lpts pifib hardware dynamic-flows location 0/1/CPU0
 flow bgp known max 1800
 flow rsvp known max 0
!

  3. Verify the configured limits and entry counts for the location.

    Example:

    Router# show lpts pifib dynamic-flows statistics location 0/1/CPU0
Dynamic-flows Statistics:
 -------------------------
 (C - Configurable, T - TRUE, F - FALSE, * - Configured)
 Def_Max  - Default Max Limit
 Conf_Max - Configured Max Limit
 HWCnt    - Hardware Entries Count
 ActLimit - Actual Max Limit
 SWCnt    - Software Entries Count
 P, (+)   - Pending Software Entries
 
 
  FLOW-TYPE           C  Def_Max Conf_Max     HWCnt/ActLimit      SWCnt  P
 -------------------- -- ------- --------   -------/--------    -------- -
 ..
 OSPF-uc-default      F        0       --         0/0                 1  +
 BFD-default          F        2       --         2/2                 2  
 BFD-MP-known         T       40       --         1/40                0  
 BGP-known            T*    2400     1800         6/900               6  
 ..
 RSVP-known           T*     300        0         0/0                 1  +
 SNMP                 T      300       --         8/300               8
 SSH-known            T       40       --         0/40                0
 SSH-default          T        1       --         1/1                 2  +
 HTTP-known           T       40       --         0/40                0
 ..
---------------------------------------------------
 Active TCAM Usage : 13421/16000 [Platform MAX: 16000]
 HWCnt/SWCnt       : 65/88
---------------------------------------------------

    An asterisk identifies a configured flow type. Confirm that BGP-known reports the configured maximum and that RSVP-known reports an actual limit of zero.

The target line card uses the configured dynamic-flow limits without exceeding its reported TCAM capacity.